The present invention relates to a device for separating oils, grease, fats and solid particles such as food scraps from waste water before the water enters the sewage or drainage system.
Restaurants and other establishments dealing in the manufacture, processing, serving and sale of food can generate large quantities of waste water. Such waste water may be generated in a food processing step or simply from the washing of cookware, utensils, crockery, cutlery and other items used in the processing and serving of food. This waste water which typically contains large quantities of oils fats, grease and food scraps often ends up in drainage or sewerage systems and leads to pollution of waterways and the clogging of drains.
The disposal of food wastes in water into the drainage and sewerage systems is accordingly, highly undesirable and in recent times the governmental authorities of many countries have moved to set stricter criteria as to the levels of food wastes that may enter these waste water disposal systems.
It would be desirable to provide a device that readily substantially separated grease, fats, oils and other wastes including food scraps from waste water before that water entered the sewage and drainage systems.
According to a first aspect, the present invention consists in a device for separating oleaginous matter from a waste fluid, the device including a chamber having a fluid inlet and a fluid outlet between which a fluid may pass through the chamber and containing a plurality of members disposed in the fluid flow path between the inlet and outlet, at least the outer surfaces of the members being oleophilic so as to attract and separate the oleaginous matter from the fluid passing through the chamber.
In the present specification, the term xe2x80x9coleaginous matterxe2x80x9d is to be taken to include oils, fats and grease whether it be in the form of a solid or liquid.
In one embodiment, the chamber comprises an upright cylinder closed at a first upper end and a second lower end. Within the chamber, the plurality of members can substantially fill the chamber.
The members can each comprise a rod of oleophilic material or a material that has been rendered oleophilic. The rods can have an outer surface with few or no corners. The rods are preferably solid cylindrical rods. In one embodiment, the rods are a polymeric material, preferably polypropylene. The polypropylene rods may be etched or micro-blasted prior to use to increase their oleophilic properties.
The plurality of members in the chamber can be aligned and extend from the first end to the second end. The rods are preferably closely packed and so arranged that any oleaginous matter, including globules of oil or a solid particle, if travelling perpendicularly to the alignment of the rods must move in a non-linear path thereby increasing the likelihood of this matter striking or being attracted to a member. The members are preferably packed in concentric rings with the spacing between the members in each ring decreasing from the outer ring to the inner ring. This spacing ensures that as any oleaginous matters moves through the chamber, the likelihood of it striking or being attracted to a member increases from the most outer ring to the most inner ring. The members can be packed in two concentric rings only.
The concentric rings and members are preferably disposed around a central outlet in the second lower end of the chamber. The outlet can have a mounting for connecting the outlet to a drainage pipe. In one embodiment, the drainage pipe can have a first outwardly extending portion, an upwardly extending portion, a second outwardly extending portion, and then a downwardly extending portion so as to form an upwardly extending S-bend. The height of the second outwardly extending portion relative to the height of the outlet of the chamber sets the minimum depth of the fluid in the chamber when in use. In another embodiment, the outlet can have an extension pipe that extends upwardly into the chamber. The upper end of the upward extension of the outlet preferably extends into an opening of a larger pipe extending downwardly from the first end and so forming a baffle through which the fluid exits the chamber. The height of the outlet extension into the chamber in this embodiment sets the minimum height of the fluid in the chamber at any one time to thereby form an airlock.
In a preferred embodiment, the outlet of the chamber can be mounted over a fluid holding container. In such an embodiment, the drainage pipe will preferably extend outwardly from the end of the holding container proximate its connection to the fluid outlet of the chamber. The fluid holding container can preferably be used to contain a quantity of bacteria that preferably are capable of breaking down oleaginous matter. The bacteria can be added to the holding container deliberately. Alternatively, natural bacteria already present in the oleaginous matters call be relied upon to colonise the holding container during use. In use, the holding container would normally fill with fluid draining firm the chamber with the majority of the fluid only exiting the holding container when the fluid level reaches a depth sufficient to drain through the drainage pipe extending outwardly therefrom.
In one embodiment, a number of fluid inlets can be provided into the chamber. Each fluid inlet preferably comprises an orifice in the cylindrical outer surface of the chamber. The inlet can comprise a small pipe that is preferably disposed substantially perpendicularly to the longitudinal axis of the members and substantially tangentially to the surface of the chamber. Each fluid inlet is preferably disposed adjacent the second lower end of the chamber. This arrangement serves to ensure that the waste fluid swirls into the chamber with the oleaginous matter being directed into the array of members.
The chamber in turn can be disposed within a larger vessel. The larger vessel preferably comprises a multi-sided upright vessel having a first upper end and a second lower end. In one embodiment, the vessel can be substantially octagonal in horizontal cross-section.
The chamber of the separating device is preferably mounted adjacent the first upper end of the larger vessel. In use, the vessel is preferably adapted such that the fluid level in the vessel is maintained above the fluid inlets of the chamber.
The larger vessel preferably has an inlet located proximate its upper end and arranged to direct the waste fluid substantially tangentially into and around the perimeter of the vessel. Heavy particles, such as heavy food scraps, are preferably expelled in the fluid to proximate the wall of the larger vessel where they slow down and sink to the bottom of the vessel for later recovery.
Oil and other similar oleaginous matter in the waste fluid will preferentially rise to the surface of the waste fluid in the vessel and so be prevented from entering the inlets of the chamber surrounding the separating device by the chamber wall.
Fine oil particles and smaller food scraps that do enter the fluid inlets of the chamber are directed into the separating device as described above.
The device is preferably arranged to trap oils, grease, fats and food particles in waste water produced by restaurants and other establishments involved in the production, processing serving and sale of food.
In a still further aspect, the present invention comprises a method for separating oleaginous matter from a waste fluid including the steps of feeding the waste fluid through the separating device according to the first aspect of the present invention and separating the oleaginous matter therefrom.
In yet a further aspect, the present invention comprises a method for treating waste fluid containing oleaginous matter including the steps of feeding the waste fluid into the larger vessel defined herein and separating the oleaginous matter therefrom.